Method and apparatus for aplying protective metal



March 24, 1942.

R. 1.. WAGNER METHOD AND APPARATUS FOR APPLYING PROTECTIVE METAL FiledJune 28, 1940 5 Sheets-Sheet 1 lNVENTORr ROBERT L. WAGNER ATTQRN EYMarch 24, 1942. ER 2,277,571

METHOD AND APPARATUS FOR APPLYING PROTECTIVE METAL Filed June 28, 1940INVENTOR ROBERT L. WAGNER 3 Sheets-Sheet 2 I ATTORNEY March 24, 1942. R.L. WAGNER METHOD AND APPARATUS FOR APPLYING PROTECTIVE METAL Filed June28, 1940 3 SheetS-Sheet S INVENTOR ROBERT L. WAGNER I ATTORNEY PatentedM... 24, 1942 METHOD APPARATUS FOR, APPLYING PROTECTIVE METAL Robert L.Wagner, Niagara Falls, N. Y., assignor to Haynes Stellite Company, acorporation of Indiana Application June 28, 1940, Serial No. 342,913

9 Claims.

This invention relates to the formation of layers of protective metalunited to articles subject to wear or oxidation or both. The inventionis particularly useful for forming annular layers of protective metal,for instance an alloy of cobalt, chromium, and tungsten that has greatresistance to abrasion and to oxidation at high temperatures, on sucharticles as valves and valve seats. For the sake of conciseness andclarity, this use of the invention will be described in detail; but thatother and analogous uses of the invention are possible will be apparent.

The seating surfaces of valves and valve seats are frequently provided.with surface layers of protective metal by a hand operation usingfusion-deposition welding methods, a welding rod, and a torch flame orother source of high temperature heat. This manual method is slow,producing in a typical case only 14 surfacedvalve parts per hour perwelder. The layers so produced have the surface irregularities andimperfections inherent in manual work of this kind, and a substantialpercentage of the welded'valve parts must be rejected or rewelded. Metalcan not be deposited manually as a smooth layer of uniform thicknessand, consequently, a substantialexcess of metal must be applied andthereafter removed during the finishing operations.

Thus, the manual method involves a waste of time, labor, and materials,and there is a demand for automatic or semi-automatic methods andmachines that decrease or eliminate this waste. It is an object of thisinvention to provide such a method and machine. A further object is toprovide a method of preparing valve blanks, valve-seat blanks, andsimilar articles to receive layers of protective metal. The manner inwhich these and other objects of the invention are at tained will becomeapparent'as the. description 'of the invention proceeds.

Typical embodiments of the several features of the invention areillustrated in the accompanying drawings. in which Fig. l is a frontview, partly in section, of a i machine for applying annular layers ofprotective metal to the seating surfaces of valve parts;

Fig. 2 is a top view of the machine shown in Fig. 1;

Fig. 3 is a detail section of an individual work table W shown in Figs.1 and 2, with a valve seat 92 thereon ready for the application of alayer of protective metal;

Fig. 4 is a section of a torch T with vertical tips, shown in Fig. 1;

Fig. 5 is a section of the torch T on the line 55 of Fig. 4;

Fig. 6 is a partial section ofanother type of torch T, with horizontaltips, shown in Fig. 1

Fig. '7 is a top view, partialhr in section, of the torch T; r

Fig. 8 is a side view of a portion of an alternative form of the torchT' having tipsin two rows;

Fig. 9 is a section, in perspective, of a valve seat blank of one typeprepared for theapplication of a layer of protective metal M;

Fig. 10 is a partial section, in perspective, of another type of valveseat blank 92, fitted to a refractory insert 93:.

Fig. 11 is a partial section, in perspective, of another type of valveseat blank 96 fitted to a refractory insert v Fig. 12 is a section, inperspective, of a partially completed valve seat 92 provided with awelded on layer 96 ofprotectlve metal;

Fig. 13 is a section, in perspective, of a completed valve seat 92having agseating surface formed in the layer 96 of protective metal;

Fig. 14 is a partial section, in perspective, of a poppet-valve head 91prepared for the application of a layer of protective metal;

Fig. 15 is a partial section, an alternative form of poppet-valve head98 fitted with a refractory sleeve or ring 99; and

Fig. 16 is a section, in perspective, of a valve gate it!) having twoseating surfaces protected with layers I06 and m2 of protective metal.

Although the apparatus illustrated'in Figs. 1

to 8 may be operated in many different ways and may be used to treatmany different articles, it will possibly find its greatest use in theapplication of annular layers of protective metal to the seatingsurfaces of valve parts, and in such use the following procedure ispreferred.

According to the preferred procedure, the valve partand protective metalare suitably prepared and then gradually heated throughout to atemperature just below the melting temperature of the protective metal,and the protective metal is then brought 'to its melting point. Thesurface of the valve part is not melted to any substantial depth.Under'such conditions, complete union of the protective metal with thevalve part occurs with a minimum danger of damage to the valve part.Excessive melting of valve part metal and commingling or alloying of thelatter with the molten protective metal are avoided. Commingllng of thevalve part metal andprotective metal dilutes the latter and is thereforeundesirable.

In practice, when providing steel valve parts in perspective, of

' ably be an aliquot part of the preheating time.

The metal valve part should have a melting point not much lower, andpreferably higher, than that of the protective surfacing metal or alloy.

Typical methods of preparing valve-part blanks for treatment areillustrated in Figs. 9. 10, 11, 14, and 15. For example, a-groove may beformed in that portion of the blank on which the protective metal is tobe applied, as shown in Figs. 9 and 14, and pieces' SI of protectivemetal, with or without a suitable powdered flux 89, may be placed overor in the groove as shown in Fig. 9. Alternatively, a bevel or chamfermay be formed in the blank, and a suitable refractory insert, ring, orplug, may be fitted to the blank I to form a groove to hold theprotective metal, as

shown in Figs, 10, 11 and 15. Instead of separate pieces of protectivemetal, a substantially complete ring of such metal may be used; or theprotective metal may be fed to the blank at a uniform rate in the formof a rod of such metal.

A prepared blank and associated-parts, such as shown in Fig. 3, may be.mounted on a work table W as indicated in Figs. 1- and 2, and subjectedto-high temperature flames in anlurality of successive steps whichincludes preheating the blank and the protective metal, melting theprotective metal, and welding the latter to the blank. The welded blankis then removed from the work table, and at this stage has an appearancesimilar, for example, to the article shown in Fig. 12. A grinding orother machining operation may then be performed to prepare the finishedvalve part, which may have the shape illustrated in Fig. 13.

An apparatus for automatically or semi-auto-' matically applyingpreheating and melting for rotation on a spindle supported on arotatable platform I 0. The latter is provided with suitable mechanismfor positioning each table successively under preheating torches T and Tand a melting torch T", in preselected relation to each torch.

The individual work tables W, shown in detail in Fig. 3, are identicaland comprise a work positioning member 30, of copper or other suitablematerial, resting upon a refractory member 3i that in turn rests upon ametal plate 32 secured to a shaft 33. The shaft 33 is supported by theplatform l through a hearing 34 and by a base I! through a bearing 35.The shaft 33 and the members supported thereon may be rotated at auniform selected rate by a drive chain 38 and a sprocket 31. The drivechain 35 is driven by a sprocket 38 that is rotated by a shaft 39 drivenby a motor 23 through be el gears 24. Electric current for the motor 23may be supplied through a brush and slip ring device 22.

Ten work tables W are shown in Fi s. 1 and 2.

This has been found to be a suitable number:

but more or fewertables may be used if desired.

The tables are disposed at equal distances apart in a circle on aplatform if) provided with a spindle housing and reinforcing member l2.The platform I0 is fastened to a rotatable main shaft 3 that issupportedon a frame I4 by suitable bearings l5 and 16. The shaft l3 andthe'platform ID are intermittently rotated at a selected rate by aratchet l1 and pawl l8 'driven by a reciprocating arm l9 connectedthrough a cam 20 to a motor 2|. In the modification shown in Fig. 1 thethrow of the cam 20 is sufilcient to rotate the table i0 one-tenth of arevolution for each revolution of the cam 20. At the end of each strokeof the cam 20, the motion of the platform I!) ceases, and the platformmay be held in position by a resilient stop 46 engaging shallowdepressions in the edge of the base ll until cam 20 is again actuated.

Supported above contiguous work tables W in the direction of movement oftable In and in fixed relation to the frame H, in the modification shownin Figs. 1 and 2, are respectively a top preheating torch T, a sidepreheating torch T, and a melting torch T". The torches are suppliedwith a combustible mixture of fuel and oxygen from a manifold 45. Whilethe apparatus shown in Figs. 1 and 2 is designed to rotate in aclockwise direction, a reverse arrangement may of course be used if theparts are appropriately transposed. In the arrangement illustrated, 'avalve part blank or other article is placed, during each dwell andeither by hand or by a suitable mechanical device, on each work table Wahead of the top preheating torch'T. The platform i0 carries each worktable to and past the torches T, T, and T", and the treated article maythen be removed from its work table by hand or mechanically during adwell of the intermittently rotating platform I 0.

As the platform [0, carrying the work tables with the. articles to betreated, moves intermittently at equal fixed intervals of time, and byequal portions of a revolution, each work table is brought successivelyunder the respective torches .T, T, and T" and emains under each torchfor a predetermined constant time interval. Each of the work tables iscontinually revolved at the same uniform rate by the motor 23, wherebyuniformity of heating of each article is promoted. If desired. as eachwork table reaches the melting torch T", a flux may be placed on thearticle being treated. This may be effected, for example, by an injector25 connected with a flux reservoir 28 and actuated from a source of gasunder pressure. A short blast f gas may be supplied to the injectorv 25by the operation of a quick-acting valve 21, actuated by a lever 28connected to the reciprocating arm is. It may also be desired to'confine the heat of the torches T,'T and T" by a hood 2!! that does notrotate with the platform i0. Such hood preferably contains one or moreapertures or transparent sections (not shown) to permit visualinspection of the torches T, T' and T". A suitable top preheating torchT is shown in detail in Figs. 4 and 5 and comprises anannular manifoldchamber ll by a conduit 42, and the manifold chamber ll supplies themixture to a row of torch tips 43. A cooling water chamber 44 at leastpartially surrounds the manifold chamber 41. If desired, for instancefor convenienc'e in the treatment of the under sides of poppet-valvevheads, the torch body 40 may be formed in two or more separate parts ina manner similar to that used in the construction of duits 63 and 13exposed to high temperature heat are protected by a cooling water jacket14. and

tation of each tableat one or more stations remotely from the heatingstations. If desired, the flux dispensing mechanism may be omitted, oran equivalent device may be used.

' Uniformity of heating of the valve parts is promoted by the uniformslow rotation of the work tables W, suitably. at a speed of 30 to 0 R.P. M.;

- by supporting the valve part being surfaced upon cooling water leavingsuch jacket" is conducted to the cooling water passages 62 and 12 of thetorch bodies 60 and 10; If desired, as in the treatment of relativelythick articles, the torch tips 43 may be arranged in two or morerows asshown in Fig. 8, the tops of each row preferably being staggered withrespect to those of the next adjacent row. The side preheating torch Tis supported at such a height above the platform 10 that the torch tips43 are opposite the sides of the valve seat blank 92. If poppet-valveheads are to be heated, the jacket H should be, far enough above thebodies 80 and 10 to clear the spindle of the valve head.

The melting torch T" may be substantially the same as the top preheatingtorch T, although more torch tips 43 should ordinarily .be used in themeltingtorch than in the preheating torch.

In each of the torches T, T, and T", the central opening acts as achimney for the products of combustion.

Instead of being mounted in fixed position, as illustrated, one or moreof the torches may be given a uniform selected rotary or' transverseoscillatory motion on an axis coaxial with that of the annular valveseating surface, and in such a case it may-be desired not to rotate thework tables.

Fewer or more preheating torches than the two illustrated may be used ascircumstances may dictate, and although it is usually preferred to applya top preheating torch before the side preheating torch, some articlesmay require the reversal of this order or the use of either toppreheating alone or of side preheating alone. Furthermore, both topflames and side flames may be-applied simultaneously. at a sacrifice ofconvenience, preheating means other than torch flames-21 muiiie furnacefor instance-may be used.

The melting torch T" may be followed by any suitable means for delayingor retarding the solidification of the molten protective metal, and suchmeans will in some instances improve the =soundness of the depositedmetal.

The platform It) need not be circular, of course, and it may be replacedby an equivalent means for transporting the work tables, for instance byan endless chain or belt moving intermittently, step by step at aselected rate. in either a horizontal plane or in a vertical plane.

- The work tables may all be rotated simultaneously, as illustrated. orthey may be provided with individual separate driving mechanisms topermit independent control of the time and rate of rotation of each worktable. It is easier to place work on, and to remove articles from, thework tables if provision is made to stop the roa member 30 of a metalsuch as copper having a. good heat conductivity and by applying thepreheating and weld'ng heat in identical manner to each of a successionof work pieces by means of a plurality of torch tips 43. At the speedsof rotation just indicated. and the total preheating time of twentyseconds and melting time of ten seconds,ment ioned above, each part ofthe metal to be heated passes under each flame a number of times. Therate of heating may be regulated by the rate of supply of combustiblegas mixture to the torches, and by the number and sizes of the torchtips 43. The number and distribution of the torch tips 43 may be variedby replacing some of the tips 43 by plugs.

An excess-acetylene oxyacetylene flame is preferred as the heatingmedium at each of the heating and melting stages.

If the preferred procedure described above is used, it is possibletoapply two layers of protective metal, one on eachside of a valve part,as-- illustrated in Fig. 16, by applying one layer, turning the partover, and applying the secondlayer. Inasmuch as only the topmost layeris raised to a melting temperature, the application of the second layerdoes not remelt the first.

In addition to the advantages described above, of rapidity of operation,efficiency in the utilization of materials and labor, uniformity of thequality of the products, and adaptability to a wide variety of surfacingprocedures, the method and apparatus of the invention insure theproduction of sound, homogeneous surface layers of protective metal freefrom laps and thoroughly-bonde'd to the metal of the article. Materialsother than Stellite, for example bronze, Monel metal," and high chromiumsteel, may of course be applied as protective metals. Not only valveparts, but also other articles such as circular shears, wearing rings,punches. core drills, and various dies including extruding dies, may betreated as described herein.

This application is in part a continuation of ry application Serial No.211,367, file'd June 2, 1938.

I claim: I

1. Method of forming a seating surface of protective metal on preformedreceiving surface of a valve part which comprises placing the valve parton a rotatable work table; advancing said work table successively to atleast 'one preheating station and at least one melting station, andmaintaining the work table-at each of said stations for the same lengthof time; introducing protective metal onto said receiving surface inwork table a plurality of revolutions during the application of saidhigh temperature flame.

2. Method offorming an annular seating surface of protective metal on avalve part which comprises removing metal from a portion of the valvepart to receive the protective metal; placing on such portion an amountof said protective metal approximately equal to the amount of metalapplying substantially vertical high temperature melting flames to theprotective metal at the melting station; at each station, rotating thearticle relative to the flames for a plurality of revolutions; applyingthe melting flames for atime only sumcient to melt the protective metaland to bond the same to the valve part; and maintaining the work tableat each of saidstations for the same length of time.

3. In a method of forming an annular deposit of protective metal on apreformed receiving surface of a metal valve part or the like, whereinsaid receiving surface is brought-to an elevated preheat temperaturebelow its melting point by applying thereto high temperature flame andsaid protective metal is melted, deposited on, and bonded to, saidpreheated receiving surface by applying high temperature melting flameto said protective metal, the improvement which consists in rotatingsaid valve part or the like relative to each of said flames for aplurality of revolutions, whereby all of the receiving surface ispreheated before any protective metal is melted and whereby thedeposited protective metal is subjected a plurality 01 times to eachmelting flame. 1

4. In apparatus for applying layers of surfacing metal to metalarticles, a plurality of work tables supported at equal distances; meanson each table to hold an article and surfacing metal in position fortreatment; means providing a zone of preheat; means providing a zone ofmelting heat; means for positioning each successive work table first inthe zone of preheat and then in the zone of melting heat, suchlast-mentioned means including means for maintaining each table in thezone of melting heat for a time that is an aliquot partof the time suchtable is in the zone of preheat.

5. Apparatus for applying layers of surfacing metal to ,metal articleswhich comprises a platform; a plurality of work tables supportedv in acircleby the platform, the distance between adjacent tables being thesame aliquot part of the circumference of such circle; means to rotatesaid platform by aliquot portions of one revolution, saidportionsbearing the same relation to an entire revolution as the said distancebetween adjacent tables bears to the said circumference; a holder oneach table adapted to hold an article and surfacing metal in positionfor. treatment; a torch for producing a high temperature flame toprovide a zone of preheat on a portion of 'said circle; and a torch forproducing a high temperature flame to provide a melting zone adjacenttoand following the zone of preheat.

6. In apparatus as defined in claim 5, means to rotate each work tableabout its axis independently of the rotation of said platform.

7. In apparatus as defined in claim 5, a torch constructed and arrangedto provide a substantially vertical preheat flame and a separate torchconstructed and arranged to provide a substantially horizontal preheatflame.

8. In apparatus as defined in claim 5, means for intermittently applyingwelding flux to the surfacing metal within the welding zone.

9. Apparatus for applying annular layers of protective metal to theseating portions of circular valve parts which comprises a rotatablecircular platform provided with means for rotating such platformintermittently; a plurality of rotatable work tables supported in acircle by the platform, the distance between adjacent tables being thesame aliquot part of the circumference of said circle, each table beingadapted to hold a valve part and a supply of protective meta] inhorizontal position for treatment and each work table being providedwith means to rotate such work table about its axis; a stop cooperatingwith said platform to limit the rotation of said platform to aliquotportions of one revolution. said portions bearing the same relation toan entire revolution as the said distance between adjacent tables bearsto said circumference; a substantially vertical annular preheat torchproviding a flame directed downward towards a portion of said circle; atorch providing a substantially horizontal flame directed inward andadapted to apply preheat to the sides of a valve part on awork table;and a torch providing a substantially vertical annular melting flamedirected downward towards another portion of said circle.

ROBERT L. WAGNER.

